In accordance with the progress of downsizing, thinning, multi-functioning, and weight reduction of various electric/electronic apparatuses, various kinds of components mounted on circuit boards assembled in these apparatuses are also increasingly required to be downsized and thinned. This has also increased a demand for downsizing (space saving) and thinning (height reduction) of connector structures which are interconnection points for electrically connecting the circuit boards to one another and the components to one another.
Conventionally, a main type of female connectors and male connectors, especially, of the female connectors was a two-row type which was manufactured by punching a thin metal plate material into a predetermined shape in a die to form two rows of female terminal portions on both end portions of its surface along a longitudinal direction, drawing out output/input terminals sideways like centipede legs from the respective female terminal portions, and resin-sealing the whole structure. By solder-mounting the output/input terminals of this female connector on pads of a predetermined circuit board and assembling a male connector being a mating member to the female connector, an intended connector structure was formed.
However, in the case of the conventional connector structure formed by this method, it was difficult to reduce a height of connection portions of the both connectors to 1.0 mm or less, and it was also difficult to narrow a pitch (interval) between the output/input terminals to 0.4 mm or less, and therefore, this structure has confronted a limit in terms of further space saving and height reduction of the connector structure.
In order to solve such a problem, there has been proposed a connector structure in which a flexible circuit board is used as a base, and by applying a plating technique, a photolithography technique, and an etching technique, a female connector in which female terminal portions constituted by, for example, slit openings are arranged in matrix is integrally formed on the flexible circuit board, a male connector having bump-shaped male terminal portions plated with, for example, copper is similarly formed on a flexible circuit board, and the male terminal portions are inserted to the female terminal portions to assemble the both connectors (refer to Patent Literature 1).
There has also been proposed a connector structure in which, by applying a plating technique, a photolithography technique, and an etching technique, a single female connector having a structure in which female terminal portions are arranged in matrix is manufactured on an insulating film, a single male connector having a structure in which male terminal portions are arranged in matrix is similarly manufactured on an insulating film, and the both are assembled. In this case, the female connector and the male connector are both mounted, with predetermined portions located on rear surfaces of the female terminal portions and the male terminal portions being soldered to pads of circuit boards on which the both connectors are mounted respectively, and these portions function as output/input terminal portions of the respective circuit boards (refer to Patent Literature 2).
In the cases of the connector structures disclosed by these Patent Literatures, as compared with the conventional two-row type connector structure, space saving is greatly realized since the connection portions of the both connectors are arranged in matrix, and height reduction is also realized since the thin insulating films are used as base materials. Further, it is also possible to meet the requirement for multi-functioning of components since the number of pins of the connection portions can be increased while space saving is ensured.
The core techniques disclosed by these Patent Literatures lie in that the female terminal portions of the female connector are constituted by the slit openings formed in pad portions composed of the thin insulating film having flexibility and a metal material covering its surface, and the male terminal portions are inserted to the slit openings, whereby the male terminal portions are retained by elasticity of the insulating film and the metal material, and at the same time, electric conductive structures are formed.